Acute Treatment and Long-term Assessment of Adult Infectious Meningitis

This is a middle-income real-world prospective clinical registry study. Clinical and laboratory data will be collected during hospitalization and follow-up visits after discharge.

Data collection will include empirical antibiotic therapy timing and type, time from hospital admission to antibiotic's first dose, corticosteroid therapy initiation, vaccination status per the Brazilian National Immunization Program, neurological sequelae and access to specialized rehabilitation services post-discharge.

Primary outcome will be all-cause mortality. Secondary outcomes will be length of hospital stay, rate of re- hospitalization, sensorineural hearing loss incidence, etiology-specific mortality, functional outcomes (measured by modified Rankin Score and Barthel Index Brazilian version), guideline-based therapies by etiology, neurological sequelae incidence stratified by etiology (e.g., motor deficits, cerebrovascular complications), adverse events, incidence of use of post-meningitis assistive devices and access to rehabilitation.

Findings will be used to inform public health system and clinical care in Brazil.

Inclusion criteria

Both sexes, aged ≥ 18 years, meeting one or more of the criteria (A, B or C) below:

--> Criterion A: Clinical presentation compatible with a suspected case of meningitis or meningococcal disease:

Fever ≥ 37.8 °C (axillary) associated with at least two of the following:

• Severe headache
• Vomiting
• Altered level of consciousness (confusion, drowsiness, irritability)
• Photophobia
• Seizure OR Fever associated with one of the classic signs of meningeal irritation (neck stiffness, Kernig or Brudzinski signs) OR Sudden-onset fever with petechial rash or hemorrhagic suffusions

• Criterion B: Cerebrospinal fluid with leukocytes ≥ 5 cells/mm³ (corrected for red blood cell count at 1:500)
• Criterion C: Confirmed etiological diagnosis of meningitis or meningococcal disease with no more than 48 hours between pathogen confirmation and signature of the informed consent form by the participant or legal representative.

Exclusion criteria

• Refusal to provide consent for the study.
• Presence of a neurological condition, other than meningitis, that accounts for the current clinical picture.
• Clinical, laboratory or radiological evidence of an alternative infectious focus that accounts for the current clinical picture.
• Use of an intraventricular device prior to study inclusion.
• Etiological diagnosis of meningitis or meningococcal disease confirmed more than 48 hours earlier.